code: def test_left_join_indexer_unique(writable):
      a = np.array([1, 2, 3, 4, 5], dtype=np.int64)
      b = np.array([2, 2, 3, 4, 4], dtype=np.int64)
      # GH#37312, GH#37264
      a.setflags(write=writable)
      b.setflags(write=writable)
  
      result = libjoin.left_join_indexer_unique(b, a)
      expected = np.array([1, 1, 2, 3, 3], dtype=np.intp)
      tm.assert_numpy_array_equal(result, expected)
  
file_path: pandas/pandas/tests/libs/test_join.py
imports: import numpy
  import pytest
  from pandas._libs import join
  from pandas._libs.join import inner_join, left_outer_join
  import pandas._testing
label_desc: Use image node_id 1 for calling a global function with example usage: test_left_join_indexer_unique(writable) without return types